Faces Defeat On His Home Turf In Tuesday’s Primary

MIAMI—At the start of his presidential bid, Marco Rubio made a fateful, strategic decision to run a national campaign rather than build momentum by targeting specific states and regions.

Now, a humiliating and campaign-ending defeat Tuesday on his home turf looms for the once-rising Florida senator.

A day after he failed to collect a single delegate from bottom-rung finishes in four far-flung nominating contests, several polls on Wednesday showed front-runner Donald Trump trouncing him in Florida by double-digit margins. He has won only two of the 24 contests so far and is running a distant third, behind Texas Sen. Ted Cruz, in the delegate count.

[…] More broadly, the-tea party movement that backed Mr. Rubio as he disavowed “amnesty’’ for illegal immigrants in the 2010 Senate race is now fractured over his sponsorship of a 2013 bill that would have allowed them to earn citizenship.

Though Mr. Rubio has walked back his support for the legislation, some tea-party activists say he has become part of the political establishment he seemed to defy in his 2010 campaign.

“Rubio talked like a tea-party person and promised us all of these conservative ideals and then he voted basically to open the borders,’’ said Howard Fein, a Port St. Lucie Republican activist who volunteered for Mr. Rubio in 2010 but is now backing Mr. Trump. “He’s never admitted he got caught up in the status quo and lost his way.’’

Meanwhile, Mr. Trump siphoned away tea-party support with his hard-line stance on immigration while putting staffers to work in Florida in November. […]